Plastic container



March 2, 1965 B. STRONG 3,171,458

msnc conmm I Filed Aug. 6,-1963 P m/mp0 sreov;

INVENTOR- United States Patent 3,171,458 PLASTIC CONTAINER BernardStrong, Beverly Hills, Calif., assignor to Strong Plastics lnc., LosAngeles, Calif., a corporation of California. v

Y iled Aug. 6', 1963, Ser.'No. 300,263 3 Claims. (Cl. 150-.5)

This invention relates in general to containers with closures andrelates more specifically to an interlocking cap and containerstructure, and to the process for installing a cap upon a container.

Interfitted container closures are at least as old as the glass milkcontainer and probably much older. Such a cap is simply rammed homeinto-a bottle mouth configuration and caused to hold by interfittingaction.

Since the first development of such interference holding devices, therehave been a great number of physical configurations and schemes for,attaching such caps. Some such schemes are very successful but have toogreat a cost. Others are less costly and have indifferent success.

It is an object of this invention to provide 'a container having anentrance opening which acts upon the cap for locking purposes, incontradistinction to prior methods having the cap lock onto thecontainer.

It is a further object of this invention to employ dilatory material forthe construction of an entrance opening into a container and causing theentrance opening to first expand and then contract after a closuredevice has been inserted into the expanded opening.

It is still another object of this invention to provide an entranceopening of a combination of physical and chemicalcharacteristicsenabling the entrance opening to be dilated along a path which causes areturn by elastic memory in such a manner that the return causes aninitial lock upon a closure device within the closure, followed by acontinuing enhancement of the interlock to a theoretical maximumattained with the passage of time.

It is still a further object of this invention to provide a containerhaving a combination of chemical properties and physical form providingimproved pour characteristics.

In accordance with these and other objects which will become apparenthereinafter, a preferred form of the present invention is disclosed inthe accompanying drawings wherein:

FIGURE 1 is a fragmentary elevational view of the top portion of acontainer, with parts broken away in section, together with a closurecap in elevation, also with parts broken away in section, the containerand cap positioned in exploded view relationship;

FIGURE 2 is a top view taken substantially along the direction of theline 22 in FIGURE 1;

FIGURE 3 is an enlarged fragmentary section of the lip of the bottle andthe channel of the cap, in the condition obtained as the cap isinstalled initially upon the container;

FIGURE 4 is the same section as FIGURE 3 with the installing deviceremoved to release the dilating force from the container, and thestructure returned toward its original condition; and

FIGURE 5 is a section taken along 5-5 of FIGURE 1.

To illustrate the invention, a classic bottle of narrow neckconstruction is employed.

The entrance opening into the bottle 10 is defined by a wall structurehaving a cross section configuration which is shaped like a questionmark in form. This form as shown in the section portion of FIGURE 1, isprovided in the manner of an expansion joint employed in large pipe lineconstruction. That is, a rounded portion 12 interconnects between a flattop wall 14 and a vertical leg section l6.

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The material from which the bottle 10 is formed is capable of beingmolded into a given form, and thereafter being forced out of thatnatural form, but so long as the material is not forced beyond itselastic limit, it will return by elastic memory substantially to itsoriginal condition. Y The preferred material for this'invention is alinear polyethylene, a thermoplastic synthetic resin.

Returning then to the physical form of the invention, an entranceopening 17 is defined by an edge Wall 18, which wall is chamfered to anacute angular edge 20 lying to the side of the wall 14 interiorly-of thecontainer, and this sloping edge wall 18 extends outwardly to a greatersectional dimension than the opening at the acute angle knife-edge 20.

Thus, because of the physical and chemical combination, the bottle 10 isprovided with an entrance opening defined by a dilatant annular edgewall having the characteristic of returning to substantially itsoriginal size and position after removal of dilating influences.

Therefore, a closure cap 22 may be installed upon this bottle 10 in anew and novel manner and gripped more strongly as time passes afterinstallation. This novel result is obtained by providing a cap 22 with acup portion- 24 formed slightly larger on the external cap surfaces thanthe natural diameter of the entrance opening 17, and then placing aplunger 26, as shown in FIGURE 3, into the cup 24 and forcing the capthrough the entrance opening 17. Such force will cause the entranceopening to dilate and to roll inwardly of the container as shown by thefull lines of the section in FIGURE 3. Note by comparison, the originalposition of theedge 20 shown in dotted outline. By so forcing the cap,the opening is both dilated and rolled upon itself somewhat, and thus isprovided with internal stresses which will tend to relieve. themselvesby causing the material to return to its original condition by elasticmemory.

Accordingly, after the plunger 26 is removed, the edge 20 immediatelyreturns toward its original condition as shown in FIGURE 4. Note,however, that the immediate return is not fully to the pre-dilationcondition shown in the dotted outline form in FIGURE. 3. Nevertheless,the edge 20 is firmly imbedded into the material of the cap 22 and thusthe cap can not be removed without first tearing or otherwise destroyingthe cap material. Furthermore, as time continues, the elastic memorywill cause the edge wall 18 to return more nearly to its originalcondition, thus increasing the interlock of the bottle into the capmaterial and enhancing the locking action, in contradistinction to ageneral relaxing available in some instances with other devices.

Because the edge 20 is a smooth knife edge, it would be quite possibleto rotate the cap around the central axis of the opening and in thismanner possibly destroy the cap and the seal created. Therefore, thewall 18 is thickened at least at one place, as shown by the referencecharacter 30 in FIGURE 1, and as seen in the sectional view of FIGURE 5.In this manner, the enlarged portion forms an interference fit whichprevents rotational movement of the cap once installed.

The material which most perfectly suits the needs of this invention ispolyethylene or othersemi-rigid plastic which has a memory. Some suchplastic materials have an inherent characteristic which repels waterand-water .based solutions or mixtures. Polyethylene is an'example. Whensuch material is employed for the containerof this invention, pouringfrom the container is virtually drip proof. Liquid projects from theedge 20 with no tendency whatsoever to cling to the surface 18 anddribble. Therefore, the combination of this material together with theform of the container edge 'constitute'sanother new and unexpectedresult of this invention.

While the instant invention has been shown and described herein in whatis conceived to be the most practical and preferred embodiments, it is.recognized that departures may be made therefrom within the scope of theinvention which is therefore not to be limited to the de tails disclosedherein but is to be afiorded the full scope said edge wall being afrustrum of a cone sloping to an acute angular edge, said frustrumsurface defining a cone projecting into the container and having an apexwhich is projectedfarther from the edge wall upon dilation of the edgewall; I

whereby, a-closure cap positioned closely within said opening whendilated will be gripped by the return thereof to its original condition.

2. A new and improved container closure, comprisingf a container havingside walls defining an axis, a dilatant end wall having an entranceopening outlined by an edge wall encompassing said axis, said end wallextending substantially perpendicular to said axis out- Wardl'y fromsaid edge wall, said' edge wall being chamfered to an acute angularedge, said edge wall being a frustrum of a cone, said frustrum defininga cone projecting into the container around said axis and having-an apexwhich is projected farther from the edge wall upon dilation of the edgewall;

said edge being to the side of said wall interiorly of said containerand the edge wall sloping outwardly .to a greater sectional dimensionthan the opening at the said acute edge; I said dilatant end wall havingan elastic memory causing the material to return substantially to itsoriginal condition after removal of dilating influences. 3. A new andimproved container closure, comprising: a container having an entrancevopening defined by a wall structure having. a cross sectionconfiguration of .question mark form having a substantially-flat saidopening encompassed by-an edge wall chamfered to an acute angular edge;

said flat top extending outwardly from said opening perpendicular tosaid vertical ,leg section;

said acute angular edge being tothe side of said edge wall interiorly ofsaid container and the edge wall sloping outwardly to a greatersectional dimension than the opening at said acute edge;

said container wall structure being of dilatant material having anelastic memory.

References Cited by the Examiner UNITED STATES PATENTS,

2,099,055 11/37 Ferngren -.5 X 2,412,169 12/46 O'Neil 53-43 I FOREIGNPATENTS 830,737 3/ 60 -Great Britain.

FRANKLIN, T. GARRETT, Primary Examiner.

1. A NEW AND IMPROVED CONTAINER CLOSURE, COMPRISING: A CONTAINER HAVINGSIDE WALLS DEFINING AN AXIS, A DILATANT END WALL HAVING AN ENTRANCEOPENING OUTLINED BY AN EDGE WALL ENCOMPASSING SAID AXIS, SAID END WALLEXTENDING SUBSTANTIALLY PERPENDICULAR TO SAID AXIS OUTWARDLY FROM SAIDEDGE WALL, SAID END WALL HAVING THE CHARACTERISTIC OF RETURNING TOSUBSTANTIALLY ITS ORIGINAL SIZE AND POSITION AFTER REMOVAL OF DILATINGINFLUENCES; SAID EDGE WALL BEING A FRUSTRUM OF A CONE SLOPING TO ANACUTE ANGULAR EDGE, SAID FRUSTRUM SURFACE DEFINING A CONE PROJECTINGINTO THE CONTAINER AND HAVING AN APEX WHICH IS PROJECTED FARTHER FROMTHE EDGE WALL UPON DILATION OF THE EDGE WALL; WHEREBY, A CLOSURE CAPPOSITIONED CLOSELY WITHIN SAID OPENING WHEN DILATED WILL BE GRIPPED BYTHE RETURN THEREOF TO ITS ORIGINAL CONDITION.